In vivo antitumor effects of carboxymethyl chitosan-conjugated triptolide after oral administration.

The purpose of this study is to evaluate in vitro and in vivo antitumor efficacy and subacute toxicity of triptolide (TP) prodrug, a conjugate between TP and carboxymethyl chitosan (CC). The CCTP conjugate contained 4∼ wt % TP and displayed excellent aqueous solubility (5 mg/mL) as compared to the native TP (17 μg/mL). In vitro cytotoxicity of CCTP conjugate was evaluated by CCK8 assay against human pancreatic cancer (PC) cell lines, showing comparable the half maximal inhibitory concentration (IC50) values to the parent TP. In a mouse model of PC (BxPC-3), the CCTP conjugate administered orally (at dose levels as low as 0.2 mg TP equivalent/kg) showed comparable efficacy in reducing or eliminating xenograft tumor to the same dose of TP, but exhibited much lower subacute toxicity as seen in body weight loss and hematological toxicity.